The effect of age and selenium on some biochemical parameters in rat liver

Two age groups, 3 and 15 mo, were used to investigate whether age-associated changes in some parameters related to lipid peroxidation occur in the liver of male Wistar rats and to observe possible effects of dietary selenium supplementation (0.25 and 0.50 ppm) for 12 mo on the same parameters. At these experimental conditions, the most important observation was that peroxidation did not change by aging, at least until 15 mo of age. In addition, the activity of Sedependent glutathione peroxidase (GSH-Px, EC 1.11.1.9) was higher in the liver of the older animals. It is suggested that the enzyme could have a role in the unchanged hepatic peroxidation observed in aged male rats. On the other hand, an effect of dietary selenium supplementation on those parameters was not observed, probably because the selenium levels were still at an adequate plateau.     

Protective role of intraperitoneally administered vitamins C and E and selenium on the levels of lipid peroxidation in the lens of rats made diabetic with streptozotocin

The aim of this work was to determine the protective effects of intraperitoneally administered vitamins C and E and selenium on the lipid peroxidation (MDA), glutathione peroxidase (GSH-Px), reduced glutathione (rGSH) activities in the lens of rats induced diabetic with streptozotocin (STZ). Lenses in the diabetic control group had a slightly higher mean level of MDA compared with lenses of the vitamin E and selenium groups, although the mean levels of MDA were significantly lower in control, combination, and vitamin C groups than in the diabetic control group (p < 0.05 andp < 0.01). However, MDA levels were significantly lower in vitamin C, vitamin E, and combination groups than in controls (p < 0.01). The GSH-Px activities of lenses were significantly higher in vitamin C-, vitamin E- and selenium-injected groups than that in the diabetic control group (p < 0.01), whereas, the activity of GSH-Px was significantly lower in the diabetic control group than in the control group. In addition, the rGSH content was seen to decrease only in the vitamin C group compared to both control and diabetic control groups (p < 0.05). In conclusion, the results from these experiments indicate that vitamins C and E and selenium can protect the lens against oxidative damage, but the effect of vitamin C appears to be much greater than that of vitamin E and selenium.     

Topiramate and Vitamin E Modulate the Electroencephalographic Records,Brain Microsomal and Blood Antioxidant Redox System in Pentylentetrazol-Induced Seizure of Rats

We investigated the effects of vitamin E and topiramate (TPM) administrations on pentylentetrazol (PTZ)–induced blood and brain toxicity in rats. Forty rats were randomly divided into five equal groups. The first and second groups were used for the control and PTZ groups, respectively. Fifty or 100 mg TPM were administered to rats constituting the third and fourth groups for 7 days, respectively. The TPM and vitamin E combination was given to animals in the fifth group. At the end of 7 days, all groups except the first received a single dose of PTZ. Blood and brain samples were taken at 3 hrs after PTZ administration. Lipid peroxidation levels of plasma, erythrocyte, brain cortex and brain microsomal fraction; nitric oxide levels of serum; and the number of spikes and epileptiform discharges of the EEG were increased by PTZ administration. Plasma and brain vitamin E concentration, erythrocyte glutathione peroxidase (GSH-Px) activity and latency to first spike of the EEG were decreased by PTZ. Plasma lipid peroxidation levels in the third group and plasma and erythrocyte lipid peroxidation levels in the fifth group were decreased compared to the second group, whereas brain vitamin C, vitamin E, erythrocyte GSH-Px and reduced glutathione (GSH) values increased in the fifth group. Brain microsomal GSH levels and EEG records in the third, fourth and fifth groups were restored by the TPM and vitamin E treatment. In conclusion, TPM and vitamin E seems to have protective effects on PTZ-induced blood and brain toxicity by inhibiting free radicals and supporting the antioxidant redox system.     

Interrelationship of antioxidative status, lipid peroxidation, and lipid profile in insulin-dependent and non-insulin-dependent diabetic patients

This study aimed to investigate the interrelationship of plasma lipid profile, lipid peroxidation, and erythrocyte antioxidative defense in patients with insulin-dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. Plasma levels of total cholesterol, triglycerides, and lipid peroxides and the activities of copper, zinc superoxide dismutase (CuZnSOD), catalase, glutathione peroxidase (GSH-Px), as well as the amount of glutathione in erythrocytes, were determined in IDDM, NIDDM, and nondiabetic control subjects. Additionally, morphology of erythrocytes in all subjects was examined. Plasma levels of total cholesterol and triglycerides were significantly increased in NIDDM compared with controls. Also, the lipid peroxide level was higher in NIDDM than in either control or IDDM subjects. CuZnSOD activity in erythrocytes was elevated in NIDDM patients compared with the control. In NIDDM patients, more extensive erythrocyte spherocytosis and echinocytosis compared with both control and IDDM subjects were observed. In contrast with the IDDM group, the observed abnormality in lipid metabolism in NIDDM patients is closely associated with increased lipid peroxidation, changes in antioxidative defense, and erythrocyte morphology.     

Selenium Supplementation Modulates Zinc Levels and Antioxidant Values in Blood and Tissues of Diabetic Rats Fed Zinc-Deficient Diet

Diabetes mellitus is associated to a reduction of antioxidant defenses that leads to oxidative stress and complications in diabetic individuals. The present study was undertaken to investigate the effect of selenium on blood biochemical parameters, antioxidant enzyme activities, and tissue zinc levels in alloxan-induced diabetic rats fed a zinc-deficient diet. The rats were divided into two groups; the first group was fed a zinc-sufficient diet, while the second group was fed a zinc-deficient diet. Half of each group was treated orally with 0.5 mg/kg sodium selenite. Tissue and blood samples were taken from all animals after 28 days of treatment. At the end of the experiment, the body weight gain and food intake of the zinc-deficient diabetic animals were lower than that of zinc-adequate diabetic animals. Inadequate dietary zinc intake increased glucose, lipids, triglycerides, urea, and liver lipid peroxidation levels. In contrast, serum protein, reduced glutathione, plasma zinc and tissue levels were decreased. A zinc-deficient diet led also to an increase in serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and liver glutathione-S-transferase and to a decrease in serum alkaline phosphatase activity and glutathione peroxidase. Selenium treatment ameliorated all the values approximately to their normal levels. In conclusion, selenium supplementation presumably acting as an antioxidant led to an improvement of insulin activity, significantly reducing the severity of zinc deficiency in diabetes.     

Selenium and Vitamin E Modulates Cigarette Smoke Exposure-Induced Oxidative Stress in Blood of Rats

Cigarette smoke contains about 5,000 chemicals that include organic and metallic compounds. The current study was undertaken to investigate the effects of selenium and vitamin E on oxidative stress-induced damage in rats exposed to cigarette smoke. Forty male rats were equally divided into four groups. The first and second groups were used as control and cigarette smoke groups, respectively. Selenium was administered to rats constituting the third group for 27 days. The Se and vitamin E combination was given to animals in fourth group for 27 days. All groups except the control, were exposed to cigarette smoke starting at the third day of the experiment and continuing for 27 days. The blood samples from all groups were taken at the end of 27 days. Plasma lipid peroxidation, triacylglycerol, and total cholesterol levels were higher in the cigarette smoke group than in the control, although erythrocytic superoxide dismutase and glutathione peroxidase activities were lower in the cigarette smoke group than in the control. The plasma lipid peroxidation, triacylglycerol, and total cholesterol levels were lower in cigarette smoke+Se+VE group than in the cigarette smoke group, although erythrocytic superoxide dismutase activity and glutathione peroxidase activity in selenium and vitamin E-administered groups were higher than in the exposed to cigarette smoke group. High-density lipoprotein-cholesterol level was not affect by selenium and vitamin E administrations. In conclusion, selenium and vitamin E seem to have protective effects on the cigarette smoke-induced blood toxicity by supporting the enzymatic antioxidant redox systems.     

Age-related changes in antioxidant defence mechanisms and peroxidation in isolated hepatocytes from spontaneously hypertensive and normotensive rats

The effects of age and hypertension on the antioxidant defence systems and the lipid peroxidation in rat isolated hepatocytes were studied. Four different age groups (1,3,6 and 12 months) were considered in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto (WKY) rats. Age-associated changes were observed on vitamin E status, glutathione (GSH) level, MDA formation and glutathione peroxidase (GSH-Px) activity in both strains. Maximal levels or activities of these parameters were found at 3 and 6 months, except for MDA which was low at 3 months. Then, a fall was observed at 12-month-old compared to 6-month values. In addition, GSH-Px activity was significantly lower in SHR than in WKY rats, except at the age of one month. The decrease of this enzyme activity could induce an increased cellular generation of radical species and lipid peroxidation, which might be link to hypertension.     

Effect of Selenium Supplementation on Lipid Peroxidation,Antioxidant Enzymes,and Lactate Levels in Rats Immediately After Acute Swimming Exercise

The present study aims to evaluate the effect of selenium supplementation on lipid peroxidation and lactate levels in rats subjected to acute swimming exercise. Thirty-two adult male rats of Sprague–Dawley type were divided into four groups. Group 1, control; group 2, selenium-supplemented; group 3, swimming control; group 4, selenium-supplemented swimming group. The animals in groups 2 and 4 were supplemented with (i.p.) 6 mg/kg/day sodium selenite for 4 weeks. The blood samples taken from the animals by decapitation method were analyzed in terms of erythrocyte-reduced glutathione (GSH), serum glutathione peroxidase (GPx) and superoxide dismutase (SOD), and plasma malondialdehyde (MDA) and lactate using the colorimetric method, and serum selenium values using an atomic emission device. In the study, the highest MDA and lactate values were found in group 3, while the highest GSH, GPx and SOD values were obtained in group 4 (p < 0,001). Group 2 had the highest and group 3 had the lowest selenium levels (p < 0,001). Results of the study indicate that the increase in free radical production and lactate levels due to acute swimming exercise in rats might be offset by selenium supplementation. Selenium supplementation may be important in that it supports the antioxidant system in physical activity.     

Protective role of intraperitoneally administered vitamin E and selenium on the antioxidative defense mechanisms in rats with diabetes induced by streptozotocin

The aim of this work was to determine the protective effects of intraperitoneally administered vitamin E and selenium (as Na₂SeO₃, Se) on the lipid peroxidation as thiobarbituric acid reactive substances (TBARS) and vitamin E levels, glutathione peroxidase (GSH-Px), reduced glutathione (GSH) activities in the plasma, red blood cell (RBC), liver, and muscle of rats with streptozotocin-induced diabetes. Fifty adult male Wistar rats were used and all rats were randomly divided into five groups. The first group was used as a control and the second group as a diabetic control. A placebo was given to first and second groups by injection. The third group was intraperitoneally administered with vitamin E (20 mg over 24 h), the fourth group with Se (0.3 mg over 24 h), and the fifth group with vitamin E and Se combination (COM) (20 mg vitamin E + 0.3 mg Se over 24 h). This administration was done for 25 days and the TBARS, vitamin E, GSH-Px, GSH levels in the plasma, RBC, liver, and muscle samples were determined. The vitamin E level in the plasma and liver was significantly (p < 0.05) higher in the control than in the diabetic control group. Also, the TBARS levels in the RBC, liver, and muscle were significantly (p < 0.05) lower in the control than in the diabetic control group. However, GSH-Px and GSH activities in RBC, liver, and muscle were not statistically different between the control and the diabetic control groups. The vitamin E levels in plasma and liver (p < 0.01 and p < 0.001) and GSH-Px activities (p < 0.01, p < 0.001) in RBC were significantly higher in vitamin E, Se, and COM groups than in both control and diabetic control groups. However, the TBARS levels of RBC, muscle, and liver in vitamin E and Se administered groups were significantly (p < 0.05-p < 0.001, respectively) decreased. These results indicate that intraperitoneally administered vitamin E and Se have significant protective effects on the blood, liver, and muscle against oxidative damage of diabetes. The abstract of this study was presented in Physiological Research 48(Suppl. 1), S99 (1999).     

Enhanced testicular antioxidant capacity in streptozotocin-induced diabetic rats

Diabetes mellitus is associated with diabetic impairment of testicular function, ultimately leading to reduced fertility. Its etiology may involve oxidative damage by reactive oxygen substances, and protection against this damage can be offered by antioxidant supplementation. The aim of this study was to investigate the effects of intraperitoneal administration of vitamin C and E, selenium (Se), and vitamin E plus Se (COM) on concentrations of lipid peroxide (as malondialdehyde; MDA), reduced glutathione (GSH), and vitamin E concentrations and glutathione peroxidase (GSH-Px) activity in the testes of rats with diabetes induced by streptozotocin (STZ). Sixty groups were used (10 animals each) and these animals were initially allocated to two groups: control group and diabetic group. The diabetic group was subdivided into five groups as follows: diabetic control (DC), vitamin E, Se, COM, and vitamin C. Animals in the DC group and vitamin C, vitamin E, Se, and COM groups were made diabetic by the injection of STZ on 4 d after an injection of vitamins C and E, Se, and COM. Those vitamins and Se were also administered for 21 consecutive days. The MDA, vitamin E, GSH levels, and GSH-Px activities in testes were determined. Although the vitamin E concentration was higher in the control than in the DC group, the MDA levels were found to be lower in the control than in the DC group. The MDA levels in the testes samples of vitamin C, vitamin E, Se, and COM groups were lower than the DC group. However, GSH-Px activity and GSH levels in the testes were not significantly different between the control and DC groups. Vitamin E concentrations in the vitamin C, vitamin E, Se, and COM groups and GSH levels and GSH-Px activities in the Se, COM, and vitamin C groups were higher than either the control or DC group. The results indicate that reactive oxygen substances may be involved in possible testicular complications in diabetes of rats. Administration of vitamins C and E and Se reduced the testicular lipid peroxidation; these vitamins and Se had significant protective effects on testes of rats against oxidative damage in diabetes. Abstract of the study was presented at the conference Trace Elements in Men and Animals-11. June 2–6, 2002; Dr. Naziroğlu has been awarded a TEMA11 Investigative Scientist Award.     

Cholesterol-rich diets have different effects on lipid peroxidation, cholesterol oxides, and antioxidant enzymes in rats and rabbits

The objective of this study was to compare the effect of cholesterol feeding of rats and rabbits. The levels of lipid peroxidation products and oxysterols in the plasma of the two species plus the antioxidant enzyme activities in the liver and erythrocytes were measured to explain their different susceptibilities to atherosclerosis. Our study showed that rats are less susceptible than are rabbits to the atherogenic effect of a cholesterol-rich diet because of differences in lipid peroxidation products as well as antioxidant enzymes activities in their livers. In rabbits, cholesterol feeding produced severe hypercholesterolemia (43-fold increase) and increased plasma and liver lipid peroxidation. Total as well as the individual oxysterol contents of 7alpha-, 7beta-hydroxycholesterol, alpha-epoxy, beta-epoxycholesterol, cholestanetriol, 7-keto, and 27-hydroxycholesterol significantly increased in the plasma of hypercholesterolemic (HC) rabbits. Erythrocyte glutathione peroxidase (GSH-Px) activity significantly decreased whereas catalase activity significantly increased in HC rabbits. In rats cholesterol feeding increased the plasma cholesterol only twofold and had no effect on plasma or liver lipid peroxidation. Only 7alpha- and 7beta-hydroxycholesterol increased and no change was observed in any of the antioxidant enzymes activity in the erythrocytes. Although cholesterol feeding caused a 10-fold increase of liver cholesterol as ester in both rats and rabbits, the antioxidant enzyme GSH-Px and catalase activities in the liver significantly increased in rats but significantly decreased in rabbits. The increase of GSH-Px and catalase activities in the liver of cholesterol fed rats could have a protective role against oxidation, thus preventing the formation of lipid peroxidation and oxysterols.     

Distribution of Selenium in Bovine Milk and Selenium Deficiency in Rats Fed Casein-based Diets,Monitored by Lipid Peroxide Level and Glutathione Peroxidase Activity

A major proportion of selenium in bovine milk was found in fluorometric analysis to be associated with the casein fraction, largely in alkali-labile form, and the rest with the whey fraction mostly in free selenite form. This uneven distribution of milk selenium seems to provide an explanation for selenium deficiency in purified caseins. The activity of glutathione peroxidase, a selenoprotein, in the liver of growing male rats fed ad libitum low-selenium diets containing either vitamin-free casein or Torula yeast 0.065 ± 0.012 or 0.015 ± 0.004 μ g Se/g diet, respectively) for 3 weeks decreased to 4 to 6% of that of the control rats fed a commercial stock diet (0.185 ± 0.092 μ g Se/g diet). Selenium status was evaluated by three different parameters for the rats assigned under pair-feeding regimen to those vitamin-free casein-based diets which were supplemented with graded levels of selenium as sodium selenite. The hepatic levels of the thiobarbituric acid-reactive substance, an indication of lipid peroxidation, decreased to control level with selenium supplementation per g diet of 0.1 μ g and over. The hepatic glutathione peroxidase activity reached a plateau above a 0.1 μ g/g diet of selenium supplementation, whereas the erythrocyte enzyme activity increased with increasing levels of supplementary selenium. These results support the notion that semi-purified diets containing vitamin-free casein as a prime protein source would not satisfy the selenium requirement of growing animals unless deliberately supplemented with additional selenium.     

Effect of fish oil supplementation on plasma oxidant/antioxidant status in rats

The aim of this study was to investigate effect of dietary omega-3 fatty acid supplementation on the indices of in vivo lipid peroxidation and oxidant/antioxidant status of plasma in rats. The plasma thiobarbituric acid reactive substances (TBARS) and nitric oxide (NO) levels, and activities of xanthine oxidase (XO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were studied in male Wistar Albino rats after ingestion of 0.4 g/kg fish oil (rich in omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid) for 30 days and compared to untreated control rats. The rats in the treated group had significantly higher SOD activity (P < 0.001), NO levels (P < 0.01) and decreased TBARS levels (P < 0.05) with respect to controls whereas GSH-Px and XO activities were not significantly different between the groups. None of the measured parameters had significant correlation with each other in both groups. We conclude that dietary supplementation of omega-3 fatty acids may enhance resistance to free radical attack and reduce lipid peroxidation. These results support the notion that omega-3 fatty acids may be effective dietary supplements in the management of various diseases in which oxidant/antioxidant defence mechanisms are decelerated.     

Enhanced testicular antioxidant capacity in streptozotocin-induced diabetic rats: protective role of vitamins C and E and selenium

Diabetes mellitus is associated with diabetic impairment of testicular function, ultimately leading to reduced fertility. Its etiology may involve oxidative damage by reactive oxygen substances, and protection against this damage can be offered by antioxidant supplementation. The aim of this study was to investigate the effects of intraperitoneal administration of vitamin C and E, selenium (Se), and vitamin E plus Se (COM) on concentrations of lipid peroxide (as malondialdehyde; MDA), reduced glutathione (GSH), and vitamin E concentrations and glutathione peroxidase (GSH-Px) activity in the testes of rats with diabetes induced by streptozotocin (STZ). Sixty groups were used (10 animals each) and these animals were initially allocated to two groups: control group and diabetic group. The diabetic group was subdivided into five groups as follows: diabetic control (DC), vitamin E, Se, COM, and vitamin C. Animals in the DC group and vitamin C, vitamin E, Se, and COM groups were made diabetic by the injection of STZ on 4 d after an injection of vitamins C and E, Se, and COM. Those vitamins and Se were also administered for 21 consecutive days. The MDA, vitamin E, GSH levels, and GSH-Px activities in testes were determined. Although the vitamin E concentration was higher in the control than in the DC group, the MDA levels were found to be lower in the control than in the DC group. The MDA levels in the testes samples of vitamin C, vitamin E, Se, and COM groups were lower than the DC group. However, GSH-Px activity and GSH levels in the testes were not significantly different between the control and DC groups. Vitamin E concentrations in the vitamin C, vitamin E, Se, and COM groups and GSH levels and GSH-Px activities in the Se, COM, and vitamin C groups were higher than either the control or DC group. The results indicate that reactive oxygen substances may be involved in possible testicular complications in diabetes of rats. Administration of vitamins C and E and Se reduced the testicular lipid peroxidation; these vitamins and Se had significant protective effects on testes of rats against oxidative damage in diabetes.     

Effect of melatonin on oxidative status of rat brain, liver and kidney tissues under constant light exposure

An enormous amount of data has been published in recent years demonstrating melatonin's defensive role against toxic free radicals. In the present study, we examined the role of melatonin as an antioxidant against the effect of continuous light exposure. Rats were divided into three groups. Control rats (group A) were kept under natural conditions whereas other group of rats (group B and C) were exposed to constant light for inhibition of melatonin secretion by the pineal gland. Group C rats also received melatonin via s.c. injection (1 mg x kg(- 1) body weight x day(- 1)). At the end of experiment, all animals were sacrificied by decapitation, serum and tissue samples were removed for determination of malondialdehyde (MDA), a product of lipid peroxidation, conjugated dienes levels and glutathione peroxidase (GSH-Px) activity levels. It was found that lipid peroxidation was increased in the rats which were exposed to constant light. Melatonin injection caused a decrease in lipid peroxidation, especially in the brain. In addition, melatonin application resulted in increased GSH-Px activity, which has an antioxidant effect. Thus, melatonin is not only a direct scavenger of toxic radicals, but also stimulates the antioxidative enzyme GSH-Px activity to detoxify hydroxyl radical produced by constant light exposure.     

The Influence of Supplements of Selenite,Selenate and Selenium Yeast on the Selenium Status of Dairy Heifers

The aim of the study was to define possible differences between selenite, selenate and selenium yeast on various aspects of selenium status in growing cattle. Twenty-four Swedish Red and White dairy heifers were fed no supplementary selenium for 6 months. The basic diet contained 0.026 mg selenium/kg feed dry matter (DM). After the depletion period the animals were divided into 4 groups; group I–III received 2 mg additional selenium daily as sodium selenite, sodium selenate, and a selenium yeast product, respectively. Group IV, the control group, received no additional selenium. The total dietary selenium content for groups I–III during the supplementation period was 0.25 mg/kg DM. After the depletion period the mean concentration of selenium in blood (640 nmol/l) and plasma (299 nmol/l) and the activity of GSH-Px in erythrocytes (610 µkat/l) were marginal, but after 3 months of supplementation they were adequate in all 3 groups. The concentration of selenium in blood and plasma was significantly higher in group III than in groups I and II, but there was no significant difference between groups I and II. The activity of GSH-Px in erythrocytes did not differ between any of the supplemented groups. The animals in the control group had significantly lower concentrations of selenium in blood and plasma and lower activities of GSH-Px in erythrocytes than those in the supplemented groups. The activity of GSH-Px in platelets was also increased by the increased selenium intake. There was no difference in the concentration of triiodothyronine (T3) between any of the groups, but the concentration of thyroxine (T4) was significantly higher in the unsupplemented control group.     

Selenium–Vitamin E Combination and Melatonin Modulates Diabetes-Induced Blood Oxidative Damage and Fetal Outcomes in Pregnant Rats

Oxidative stress is considered to be the main cause of diabetic complications. In the current study, we investigated the effect of selenium–vitamin E combination and melatonin on lipid peroxidation (LPO) and scavenging enzyme activity in the blood of streptozocin (STZ)-induced diabetic pregnant rats. Forty female Wistar rats were randomly divided into five groups. The first and second groups were used as the non-pregnant control and pregnant control groups, respectively. The third group was the pregnant diabetic group. Vitamin E plus selenium and melatonin were administered to the diabetic pregnant rats consisting fourth and fifth groups, respectively. Diabetes was induced on day 0 of the study by STZ. Blood samples were taken from all animals on the 20th day of pregnancy. LPO level was higher in diabetic pregnant rats than in control, although superoxide dismutase, catalase, and glutathione peroxidase activities were lower in diabetic pregnant animals than in control. LPO levels were lower both in the two treatment groups than in the diabetic pregnant rats, whereas selenium–vitamin E combination and melatonin caused a significant increase in the activities of these antioxidant enzymes (p < 0.01). In conclusion, vitamin E plus selenium seems to be a more potent antioxidant compared to melatonin in diabetic pregnant rats. Melatonin did not significantly affect the elevated glucose concentration of diabetic pregnant treated with melatonin group. Vitamin E plus selenium may play a role in preventing diabetes-related diseases of pregnant subjects.     

Hyperlipidemia and type I 5′-monodeiodinase activity

Male New Zealand White rabbits were divided into three groups: (I) control, (II) high-fat-diet (HFD) fed, and (III) HFD fed+selenium supplemented. After 3 mo of treatment, there was a significant increase in serum cholesterol and triglycerides in the HFD-fed group as compared to the control. However in the selenium (Se)-supplemented group, the levels of serum cholesterol and triglycerides were significantly less as compared to group II. HFD feeding resulted in decreased serum Se levels, but supplementation of dietary Se along with HFD, as in group III, showed an apparent increase in its levels. The Se-dependent glutathione peroxidase (GSH-Px) activity in the liver and the aorta increased significantly in HFD-fed animals and also showed an additional significant increase on Se supplementation. Both serum T₃ and T₄ levels showed a significant decrease on HFD feeding. However, supplementation of Se led to a significant increase in the levels of these parameters viz-à-viz HFD-fed animals. HFD feeding significantly decreased the activity of type I iodothyronine 5′-deiodinase (5′-DI) in the liver from group II rats. On supplementation of Se along with HFD, the activity increased in the liver. However, there was no significant change in its activity in the aorta. The 5′-DI activity in the thyroid showed an opposite trend in comparison with peripheral tissues (i.e., liver). The important finding of this study is that in the hyperlipidemic state, deiodinase in the thyroid behaves in a different manner as compared to its activity in extrathyroidal tissues.     

Apple Cider Vinegar Modulates Serum Lipid Profile,Erythrocyte, Kidney,and Liver Membrane Oxidative Stress in Ovariectomized Mice Fed High Cholesterol

The purpose of this study was to investigate the potentially beneficial effects of apple cider vinegar (ACV) supplementation on serum triglycerides, total cholesterol, liver and kidney membrane lipid peroxidation, and antioxidant levels in ovariectomized (OVX) mice fed high cholesterol. Four groups of ten female mice were treated as follows: Group I received no treatment and was used as control. Group II was OVX mice. Group III received ACV intragastrically (0.6 % of feed), and group IV was OVX and was treated with ACV as described for group III. The treatment was continued for 28 days, during which the mice were fed a high-cholesterol diet. The lipid peroxidation levels in erythrocyte, liver and kidney, triglycerides, total, and VLDL cholesterol levels in serum were higher in the OVX group than in groups III and IV. The levels of vitamin E in liver, the kidney and erythrocyte glutathione peroxidase (GSH-Px), and erythrocyte-reduced glutathione (GSH) were decreased in group II. The GSH-Px, vitamin C, E, and β-carotene, and the erythrocyte GSH and GSH-Px values were higher in kidney of groups III and IV, but in liver the vitamin E and β-carotene concentrations were decreased. In conclusion, ACV induced a protective effect against erythrocyte, kidney, and liver oxidative injury, and lowered the serum lipid levels in mice fed high cholesterol, suggesting that it possesses oxidative stress scavenging effects, inhibits lipid peroxidation, and increases the levels of antioxidant enzymes and vitamin.     

Venlafaxine Modulates Depression-Induced Oxidative Stress in Brain and Medulla of Rat

Venlafaxine is an approved antidepressant that is an inhibitor of both serotonin and norepinephrine transporters. Medical treatment with oral venlafaxine can be beneficial to depression due to reducing free radical production in the brain and medulla of depression- induced rats because oxidative stress may a play role in some depression. We investigated the effect of venlafaxine administration and experimental depression on lipid peroxidation and antioxidant levels in cortex brain, medulla and erythrocytes of rats. Thirty male wistar rats were used and were randomly divided into three groups. Venlafaxine (20 mg/kg) was orally supplemented to depression-induced rats constituting the first group for four week. Second group was depression-induced group although third group was used as control. Depressions in the first and second groups were induced on day zero of the study by chronic mild stress. Brain, medulla and erythrocytes samples were taken from all animals on day 28. Depression resulted in significant decrease in the glutathione peroxidase (GSH-Px) activity and vitamin C concentrations of cortex brain, glutathione (GSH) value of medulla although their levels were increased by venlafaxine administration to the animals of depression group. The lipid peroxidation levels in the three tissues and nitric oxide value in cortex brain elevated although their levels were decreased by venlafaxine administration. There were no significant changes in cortex brain vitamin A, erythrocytes vitamin C, GSH-Px and GSH, medulla vitamin A, GSH and GSH-Px values. In conclusion, cortex brain within the three tissues was most affected by oxidative stress although there was the beneficial effect of venlafaxine in the brain of depression-induced rats on investigated antioxidant defenses in the rat model. The treatment of depression by venlafaxine may also play a role in preventing oxidative stress. Abstract of the paper was submitted in 1st Ion Channels and Oxidative Stress Congress, 14–16 September 2006, Isparta, Turkey.